The proposed study is designed to explore the biological mechanism that may explain breast cancer risk-related behaviors or lifestyle. Specifically, the study will examine the insulin-like growth factor-I (IGF-I) gene expression in relation to diet, physical exercise, and other lifestyle features, as well as will compare the differences in the IGF-I gene expression between women with and without breast cancer. If the study is able to demonstrate a link between breast cancer risk and specific features of lifestyle through the IGF-I gene expression, then it will be possible to develop specific cancer prevention intervention that modifies the expression of the IGF-I gene by adopting and/or avoiding the risk-related lifestyle. This small grant application is written for a pilot study that has two primary objectives. The first objective is to develop a reverse transcriptase-polymerase chain reaction (RT-PCR) method to detect different types of the IGF-I mRNA. Two distinct IGF-I cDNA sequences have been reported. PCR primers based on the published cDNA sequences have been designed for amplification of different IGF-I transcripts in peripheral blood. Our preliminary RT-PCR experiments have shown that different IGF-I transcripts are detectable in peripheral blood. Heparinized blood specimens will be collected from women with and without breast cancer. The blood specimens will be centrifuged for isolation of white blood cells that will be used to extract total RNA for the RT-PCR analysis. The second objective of the pilot study is to establish a recruiting system for conducting a hospital-based case-control study. Newly diagnosed breast cancer patients and their age-and race-matched controls will be selected consecutively during a specified time period from a breast clinic at the Louisiana State University Medical Center in Shreveport. The Medical Center provides medical service to more than 50 percent of African Americans and every year about 130 to 140 new breast cancer patients are diagnosed and treated at the clinic. Women enrolled in the study will undergo a 30 to 45 minutes in person interview with use of a structured questionnaire and will be requested to provide 10 ml blood sample for the study.